Method for manufacturing led package

ABSTRACT

A method for making an LED package includes the following steps: providing a substrate with an electrode formed thereon; forming at least one barrier portion on the electrode; forming a reflective cup on the substrate wherein the reflective cup covers the at least one barrier portion; providing an LED die in the reflective cup and electrically connecting the LED die to the electrode; and forming an encapsulation in the reflective cup, the encapsulation covering the LED die.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional application of patentapplication Ser. No. 13/326,341, filed on Dec. 15, 2011, entitled “LEDPACKAGE AND METHOD FOR MAKING THE SAME,” which is assigned to the sameassignee as the present application, and which is based on and claimspriority from Chinese Patent Application No. 201110105037.7 filed inChina on Apr. 26, 2011. The disclosures of patent application Ser. No.13/326,341 and the Chinese Patent Application No. 201110105037.7 areincorporated herein by reference in their entirety.

BACKGROUND

1. Technical Field

The present disclosure generally relates to light emitting diode (LED)packages and method for making the same.

2. Description of Related Art

Generally, an LED package includes a substrate, an LED die arranged onthe substrate, a reflective cup formed around the LED die and anencapsulation formed on the substrate to cover the LED die. However, dueto that there are usually gaps remained between the substrate and thereflective cup, moisture and dust can easily infiltrate into the LEDpackage through the gaps, thereby leading to poor reliability and shortservice life of the LED package.

Therefore, it is necessary to provide an LED package which can overcomethe above shortcomings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the disclosure.

FIG. 1 is a schematic, cross-sectional view of an LED package inaccordance with an embodiment of the present disclosure.

FIG. 2 is a schematic, top view of the LED package of FIG. 1.

FIG. 3 is a flow chart of a method for forming an LED package inaccordance with an embodiment of the present disclosure.

FIGS. 4-8 are schematic, cross-sectional views respectively showingvarious steps of the method of FIG. 3.

DETAILED DESCRIPTION

Reference will now be made to the drawings to describe the present LEDpackages, method for making the LED packages, in detail.

Referring to FIG. 1 and FIG. 2, an LED package 10 of an embodimentincludes a substrate 11, two electrodes 12, an LED die 13, a barrierportion 14, a reflective cup 15, and an encapsulation 16.

The substrate 11 can be made of a material with excellent thermalconductivity and electrical insulation, such as PPA (polyphosphoricacid)or ceramic. In this embodiment, the substrate 11 is rectangular andthin. Referring to FIG. 5 at the same time, the substrate 11 includes afirst surface 111 and a second surface 112 opposite to the first surface111. The first surface 111 is rectangular, and includes two oppositefirst sides 113 and two opposite second sides 114 perpendicular to thefirst sides 113. Alternatively, the first surface 111 can be circular orother desired shape according to actual requirements.

Referring to FIG. 6, the electrodes 12 are formed on the substrate 11,and spaced from each other. Each electrode 12 extends from a centralportion of the first surface 111 to the second surface 112, across onesecond side 114. The electrodes 12 are spaced from the first sides 113.An insulation area 115 is thus defined between an edge of each electrode12 and a corresponding adjacent first side 113. The electrodes 12 aremade of metal with good electric conductivity, such as gold, silver,copper, platinum, aluminum, nickel, tin, magnesium or an alloy thereof.

The LED die 13 is mounted on one of the two electrodes 12, andelectrically connected to the electrodes 12 by two metal wires 131. TheLED die 13 can also be mounted on and electrically connected to the twoelectrodes 12 by flip chip bonding or eutectic bonding. Alternatively,the LED die 13 can be arranged on the first surface 111 of the substrate11 and electrically connected to the two electrodes 12 by the two metalwires 131.

The barrier portion 14 is arranged on the electrode 12. In thisembodiment, the barrier portion 14 includes two strips on the twoelectrodes 12 respectively, and sitting at two opposite sides of the LEDdie 13. Each strip spans across the corresponding electrode 12 along theextending direction of the second side 114 with two ends thereofcontacts the insulation area 115.

The reflective cup 15 is formed on the first surface 111 and covers thebarrier portion 14. The reflective cup 15 surrounds the LED die 13, andreceives the LED die 13 therein. The material of the reflective cup 15can be the same as the substrate 11, such as PPA. Moreover, thereflective cup 15 and the substrate 11 can be formed integrally as asingle piece.

The encapsulation 16 is filled in the reflective cup 15. Theencapsulation 16 is over the substrate 11 and covers the LED die 13 andthe metal wires 131. The encapsulation 16 is made of silicone or epoxyresin. The encapsulation 16 includes light transmissive fluorescentmaterials evenly distributed therein. The fluorescent materials are, forexample, YAG (yttrium aluminum garnet), TAG (terbium aluminum garnet),silicate, nitride, nitrogen oxides, phosphide and sulfide. Theencapsulation 16 protects the LED die 13 from moisture and dust andhelps the conversion of color of the light from the LED die 13 to adesired color.

The barrier portion 14 is made of a material, such as epoxy resin orsilicone, with a bonding force to the corresponding electrode 12 largerthan that of the reflecting cup 15 to the corresponding electrode 12.The barrier portion 14 is attached on and covers outer portions of theelectrodes 12. Due to that the bonding force between the barrier portion14 and the electrode 12 is larger than that between the reflective cup15 and the electrode 12, a gap between the reflecting cup 15 and theelectrodes 12 is greatly reduced by the barrier portion 14, and thusmoisture and dust outside the LED package is difficult to infiltrateinto the LED package 10 with the barrier portion 14. When the barrierportion 14 is made of epoxy resin with excellent bonding force with PPAwhich is usually employed to make the reflective cup 15, the barrierportion 14 acts as an interface layer firmly connecting the electrode 12with the reflective cup 15. Furthermore, a curved connecting surface 141is formed at each joint of the barrier portion 14 and the reflective cup15, thereby increasing the distance of the path along which moisture anddust infiltrate into the LED package from outside. Thus, the moistureand dust are difficult to reach the LED die 13 to cause a harm thereto.

Referring to FIG. 3 to FIG. 8, the present disclosure further provides amethod for making the LED package 10. The method includes followingsteps.

Referring to FIG. 4, the first step of the method includes providing asubstrate 11. The substrate is rectangular and includes a first surface111 and a second surface 112 opposite to the first surface 111. In thisembodiment, the substrate 11 is made of PPA.

Two electrodes 12 are located on the substrate 11. The electrodes 12 areseparated from each other. The electrodes 12 are made of metal with goodelectric conductivity, such as gold, silver, copper, platinum, aluminum,nickel, tin, magnesium or an alloy thereof. The electrodes 12 are madeby electroplating, magnetron sputtering, chemical plating or waferbonding.

Referring to FIG. 5 and FIG. 6, the second step includes forming abarrier portion 14 on the electrodes 12 by compression molding. In thisembodiment, the barrier portion 14 includes two strips respectivelyextending across the electrodes 12. The barrier portion 14 is made ofepoxy resin or silicone. The bonding force between the barrier portion14 and the electrode is quite large.

Referring to FIG. 7, the third step includes forming a reflective cup 15by injection molding or transfer molding. The reflective cup 15 isformed on the first surface 111 of the substrate 11 along four sidesthereof and covers the barrier portion 14 and parts of the electrodes12. A chamber is defined inside the reflective cup 15 to receive the LEDdie 13. The reflective cup 15 is made of the same material as thesubstrate 11, such as PPA. The bonding force between the reflective cup15 and the electrodes 12 is smaller than that between the barrierportion 14 and the electrodes 12.

Referring to FIG. 8, the fourth step includes fixing the LED die 13 onthe electrode 12. The LED die 13 is electrically connected with theelectrodes 12 by metal wires 131. The LED die 13 is received in thereflective cup 15 and between the two barrier portions 14 covered byreflective cup 15.

Referring to FIG. 9, the last step includes forming a transparentencapsulation 16 in the reflective cup 15. The encapsulation 16 coversthe LED die 13 and the metal wires 131. The encapsulation 11 is made ofsilicone or epoxy resin. The encapsulation 16 may include fluorescentmaterials distributed therein. The encapsulation 16 protects the LED die13 from moisture and dust.

In summary, the barrier portion 14 is disposed in the reflective cup 15and the bonding force between the barrier portion 14 and the electrode12 is larger than that between the reflective cup 15 and the electrode12. Thus, it is difficult for moisture and dust outside the LED package10 to infiltrate into the LED package 10 through the joint of thereflective cup 15 and the electrodes 12 where the barrier portion 14sits. Meanwhile, due to the blocking of the barrier portion 14 and a topof the barrier portion 14 has a curved profile, the path that moistureand dust can infiltrate into the LED package is curved whereby thelength of the path is increased. As such, the barrier portion 14effectively prevents the LED die 13 from being affected and damaged bymoisture and dust. Furthermore, the bonding force between the barrierportion 14 and the reflective cup 15 is large, so that the electrode 12,and the reflective cup 15 are joined together firmly by the barrierportion 14.

It is to be understood that the above-described embodiments are intendedto illustrate rather than limit the disclosure. Variations may be madeto the embodiments without departing from the spirit of the disclosureas claimed. The above-described embodiments illustrate the scope of thedisclosure but do not restrict the scope of the disclosure.

What is claimed is:
 1. A method for making an LED package, comprising:providing a substrate with an electrode formed thereon; forming at leastone barrier portion on the electrode; forming a reflective cup on thesubstrate, the reflective cup covering the at least one barrier portion,a bonding force between the reflective cup and the electrode beingsmaller than that between the at least one barrier portion and theelectrode; providing an LED die in the reflective cup and electricallyconnecting the LED die to the electrode; and forming an encapsulation inthe reflective cup, the encapsulation covering the LED die.
 2. Themethod of claim 1, wherein a distance is remained between an edge of theelectrode and a first side of the substrate, and an insulation area isdefined by the substrate between the edge of the electrode and the firstside, the barrier portion spanning across the electrode and contactingthe insulation area.
 3. The method of claim 1, wherein the reflectivecup is formed on the substrate along sides of the substrate, thereflective cup completely covering the barrier portion, the reflectivecup and the barrier portion surrounding the LED die and receiving theLED die therein.
 4. The method of claim 3, wherein the reflective cup isformed by injection molding or transfer molding.